Perceptions count. Homes in the Rancho Santa Fe Covenant sell for 20+% more than do similar homes located outside the covenant area. Homes in the southern area of La Jolla’s 92037 zip area sell for 20% more than similar homes on the same hill but with the 92109 PB zip.
If you’re buying for shelter San Elijo is probably the better buy. If you’re buying for resale then Carillo Ranch might be the better choice.